Pipeline isolation is used in a variety of industries where, for example, it is required to perform an operation on a section of pipe or to isolate a section of pipe in the event of a breach. In subsea environments, isolation of the pipe may be needed to prevent ingress of water into the pipe or loss of pressurized fluid, such as oil or gas, from the pipe.
Typically, isolation of a pipe may be achieved using an isolation plug and a range of high pressure, hydraulically activated, isolation plugs have been developed which, once set, retain the integrity of the isolation independently of the hydraulic activation system.
In some instances, the isolation plug may be controlled via a hydraulic umbilical. In other instances, the isolation plug may be controlled remotely, with instructions being transmitted to a remote control module via a through pipe wall communication system.
While isolation plugs such as those described above may be used effectively, the requirement for external control of the plug adds complexity and requires external interfaces to be provided on the pipe, such that it may not be practical or feasible to use existing plugs in a number of applications, for example in pipelines which travel across remote or inaccessible terrain, or in subsea applications.
In the field of subsea pipe laying, for example, high pressure isolation plugs may be required to set rapidly in the case of a pipe breach to prevent ingress of seawater. While existing remote controlled plugs may be provided with sensors which activate the plug when water ingress is detected, these plugs also suffer from drawbacks in that they are complex, have multiple failure modes, limited set cycles and still require external access to the pipe at the set location to unset the plug.